The invention relates generally to apparatus and methods for controlling the flow of fluids through a fluid dispensing system. More particularly, the invention provides a coupling and tubing arrangement configured to control the flow of liquid soap inside a soap dispensing system wherein the system includes a main soap reservoir, an auxiliary bladder reservoir and at least one pump for dispensing soap to a user.
Liquid soap dispensing systems are frequently installed in commercial and industrial restrooms. Systems of this general type commonly include at least one hand-operated pump operable to dispense liquid to a user of the system. The soap is generally supplied to the pump from some kind of reservoir. The reservoir holds a fairly large quantity of liquid soap so that a supply of the soap is continuously available. This type of system requires periodic inspection so that the reservoir can be refilled or replaced before it becomes empty. If the reservoir becomes empty, the soap will not be available when a user wants to use the system.
Very commonly, these systems will use a disposable reservoir that comes from the manufacturer pre-filled with soap. When the reservoir becomes empty, it is simply discarded and replaced with a new one. This arrangement insures a convenient supply of soap while avoiding much of the mess, inconvenience, and risk of contamination that would be present in systems using refillable reservoirs.
A disposable reservoir system is less than ideal in one important respect however. It is very undesirable in such a system that the reservoir ever become completely empty. If the reservoir is empty, soap will not be available to users of the system. Because the person maintaining the system cannot watch the reservoir continuously, that person cannot be there to replace the reservoir precisely when it runs out of soap. The person must therefore replace the reservoir at some point before it becomes empty. This means that considerable soap is wasted, with attendant needless expense and disposal problems.
To remedy this, a second reservoir is sometimes included to provide a supply of soap should the first reservoir become empty. When the first reservoir is empty, soap is drawn from the second reservoir until such time as the first reservoir can be refilled or replaced. Often, the first and second reservoir are identical and interchangeable. This configuration is less than ideal, however, because this scheme requires the system to be inspected and maintained more often than would ideally be the case.
It would be preferable to devise a system in which a relatively large main reservoir served as the main supply of soap to the system. This relatively large main reservoir, holding a relatively large quantity of soap, would require only relatively infrequent inspection and replacement. A comparatively small auxiliary reservoir could be provided to act as a reserve supply to ensure an uninterrupted supply of soap after the main reservoir becomes empty and before the main reservoir can thereafter be inspected and replaced.
In this type of two reservoir system it will be desirable that soap be dispensed first from the main reservoir, with soap being drawn from the auxiliary reservoir only when the main reservoir is substantially empty. It will be further desirable that after the previously emptied main reservoir is replaced, soap will flow automatically from the main reservoir into the auxiliary reservoir to replenish the reserve supply held in the smaller auxiliary reservoir.
Flow control to accomplish these goals might be provided in the form of one or more mechanical or electromechanical valves. But such valves, while generally well-known to those skilled in design and construction of fluid handling systems, are less than ideal for this application. Mechanical and electromechanical valves are prone to failure through jamming or plugging, for example. These types of valves are also complex and somewhat expensive for use in this kind of simple, widely-used system. Finally, electromechanical valves require a power supply to operate them and are thus expensive and prone to failure due to power interruption.
It would be highly desirable, therefore, to provide an improved system for controlling the flow of soap between a main reservoir, an auxiliary reservoir and a dispensing pump. The improved system should be simple, inexpensive and highly reliable with little or no maintenance. The present invention is embodied in such a system.
Although a preferred embodiment of the invention is described herein in the form of a user operable soap dispensing system, the invention may find use as well in any fluid handling system in which fluid is moved between main and auxiliary reservoirs and a pump or another outlet for the fluid. Thus, although a preferred embodiment is described in the form of a soap dispensing system, the scope of the invention is not so limited and no such limitation is implied herein.